Scissor frame lift apparatus for dump trucks

ABSTRACT

A scissor frame lift for pivotally moving a dump body hingedly secured to a truck frame comprising upper and lower frame assemblies having the rearward ends thereof pivotally secured together and which are pivotally moved relative to one another by a hydraulic cylinder operatively interconnecting the upper and lower frame assemblies. The lower frame assembly includes a pair of elongated frame members, the forward ends of which are operatively pivotally or rotatably secured to mounts secured to the frame members of the truck frame. The upper frame assembly includes a pair of frame members, the forward ends of which are operatively connected to mounts secured to the runsills of the truck body. The distance between the rearward ends of the frame members of the lower frame assembly is substantially less than the distance between the frame members of the truck frame and is substantially less than the distance between the forward ends of the frame members of the lower frame assembly. The distance between the rearward ends of the frame members of the upper frame assembly is also considerably less than the distance between the forward ends of the frame members of the upper frame assembly. A unique body prop is also provided which prevents bending of the scissor frame during prop function.

This invention relates to a lift apparatus and more particularly relatesto a novel and improved scissor frame lift apparatus for use inelevating the hinged dump body on a dump truck.

BACKGROUND AND FIELD OF THE INVENTION

I have previously devised novel and improved scissor frame hoistsemployed on dump trucks for the purpose of stabilizing the movement ofthe dump body as it is elevated and tilted rearwardly by a hydrauliccylinder lift mechanism. For example, reference is made to U.S. Pat.Nos. 3,809,429; 4,148,528; and 4,592,593.

For light duty trucks (15,000 lbs. and under gross vehicle weight), theconventional hoist normally used is a drop-hinge scissor hoist in whichthe scissor hinge of the hoist is dropped down below the top surface ofthe truck frame and positioned between the truck frame side rails orlong members. A typical example of a drop-hinge scissor hoist is the LowProfile LP-090 manufactured by Hydraulics Unlimited Manufacturing Co. ofEaton, Colo. In the LP-090, as well as the other typical drop-hingescissor hoists, the scissor hinge is the full width of the hoist frame.Inasmuch as the upper and lower scissor frames operate at high stresslevels, it is an advantage to have those frames disposed as straight aspossible so that forces can be carried directly therethrough withouthaving to "bend the forces around corners."

Very recently, truck chassis manufacturers have been leaving less andless room available between the frame members for the scissor hinge ofthe hoist. This is due in large amount to the encroachment of exhaustpipes, fuel tanks, brake equalizer valve linkages, and various bracketsinto the area of the hoist scissor hinge. In some cases, it isimpossible to install a conventional drop-hinge scissor hoist because ofinterference with those components.

It is therefore a principal object of this invention to provide animproved scissor frame lift apparatus for dump trucks.

Yet another object of the invention is to provide a drop-hinge scissorframe lift apparatus for dump trucks wherein the scissor hinge is not"full width" but has a width substantially less than the distancebetween the truck frame members.

Yet another object of the invention is to provide a scissor frame liftapparatus including a narrow scissor hinge which permits theinstallation of the same on some trucks which would otherwise be unableto accommodate conventional drop-hinge scissor hoists.

Yet another object of the invention is to provide a scissor frame liftapparatus for dump trucks including a narrow scissor hinge which reducesthe amount of time required for mounting the body and hoist on a truck.

Yet another object of the invention is to provide a scissor frame liftapparatus of the type described which reduces the mounting coststhereof.

A further object of the invention is to provide a scissor frame liftapparatus of the type described which permits the hoist to be mounted ondifferent sizes and types of equipment.

Yet another object of the invention is to provide an incorporated bodyprop which does not load the scissor frame during prop function.

Still another object of the invention is to provide a scissor frame liftapparatus of the type described which is economical of manufacture,durable in use and refined in appearance.

These and other objects of the present invention will be apparent tothose skilled in the art.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is an exploded perspective view of the scissor frame liftapparatus of this invention;

FIG. 2 is a top view of the apparatus;

FIG. 3 is a side elevational view of the apparatus with the phantomlines indicating the upper frame assembly having been moved toward itsupper position;

FIG. 4 is a side elevational view illustrating the upper frame assemblypivotally moved to an upper position and held in place by anincorporated body prop;

FIG. 5 is a perspective view illustrating the body prop of thisinvention;

FIG. 6 is a top view of a typical light duty truck;

FIG. 7 is a side elevational view of the truck of FIG. 6;

FIG. 8 is a side elevational view of the truck of FIG. 7 having thescissor frame lift apparatus of this invention mounted thereon with thebroken lines indicating the body pivotally moved to a dumping position;

FIG. 9 is a top view illustrating the scissor frame lift apparatus ofthis invention mounted on the truck;

FIG. 10 is a sectional view illustrating the relationship of the hoistof this invention and the body and truck frame members; and

FIG. 11 is a rear view of the scissor frame lift apparatus of thisinvention.

SUMMARY OF THE INVENTION

A scissor frame lift apparatus for dump trucks is described which isadapted to be primarily mounted on light duty trucks or the like toenable a hinged dump body to be pivotally moved to a dumping position.The scissor frame lift apparatus is designed to enable the apparatus tobe mounted between the frame members of the truck in a manner so as notto interfere with the exhaust pipes, fuel tanks, brake equalizer valvelinkages, brackets, etc. The scissor frame lift includes upper and lowerframe assemblies which are pivotally secured together at their rearwardends. The lower frame assembly includes a pair of lower frame memberswhich have a lower mount cross tube secured thereto and extendingtherebetween. The lower mount cross tube has an inner mount cross tubepositioned therein with the outer ends thereof being pivotally securedto mounts on the truck frame members. The upper frame assembly includesa pair of upper frame members having an upper mount cross tube securedthereto and extending therebetween at the forward ends thereof. An upperinner mount cross tube is received in the upper mount cross tube and hasits opposite ends rotatably secured to mounts secured to the runsills ofthe dump body. The rearward ends of the frame members of the upper frameassembly are operatively connected to a hinge shaft which is secured toand extends between the rearward ends of the frame members of the lowerframe assembly. A hydraulic cylinder is positioned between the framemembers of the upper and lower frame assemblies and has its cylinder rodoperatively rotatably secured to a cross head shaft which is secured toand which extends between the frame members of the upper frame assemblyadjacent the rearward ends thereof. The forward or base end of thehydraulic cylinder is operatively connected to a cylinder mount tubemounted on the lower mount cross tube.

The distance between the rearward ends of the frame members of the lowerframe assembly is substantially less than the distance between the framemembers of the truck and is substantially less than the distance betweenthe forward ends of the frame members of the lower frame assembly. Thedistance between the rearward ends of the frame members of the upperframe assembly is substantially less than the distance between the framemembers of the truck and is substantially less than the distance betweenthe forward ends of the frame members of the upper frame assembly.

A body prop is also provided and has one end thereof pivotally mountedon the inner lower mount cross tube and which may be moved from asubstantially horizontal inoperative position to a substantially uprightposition wherein the upper end thereof is designed to engage one end ofthe upper mount cross tube to prevent the upper frame assembly and thedump body from moving downwardly as desired.

DESCRIPTION OF THE PREFERRED EMBODIMENT

The numeral 2 refers to a conventional light duty truck including a pairof longitudinally extending side rails or frame members 4 and 4' adaptedto support a body 6 including runsills 8 and 8'.

The drop-hinge scissor frame lift apparatus of this invention isreferred to generally by the reference numeral 10 and generallycomprises a lower frame assembly 12 and upper frame assembly 14pivotally secured thereto as will be described in more detailhereinafter. For purposes of description, the apparatus of thisinvention will be described as including a rearward end 16 and a forwardend 18.

Lower frame assembly 12 includes a pair of spaced side frame members 20and 22 which extend rearwardly and inwardly from their forward ends andwhich are in the form of C-shaped channels having a top flange TF,bottom flange BF, and web W. As seen in the drawings, the webs W of theframe members 20 and 22 extend inwardly and rearwardly from theirforward ends to their rearward ends. It can also be seen that the widthsof the flanges TF and BF increase from the forward to rearward endsthereof. The vertical height of the webs increases from the forward torearward ends also.

The rearward ends of side frame members 20 and 22 have scissor hingelegs 24 and 26 secured thereto which extend downwardly from therearwardly ends of the webs W at the inner surfaces thereof. Scissorhinge shaft 28 is mounted in and extends between and is secured toscissor hinge sleeves or rings 30 and 32 which are welded to hinge legs24 and 26 respectively. Lower mount cross tube 34 is welded to theforward ends of side frame members 20 and 22 and has a cylinder mounttube 36 rotatably mounted thereon between the side frame members 20 and22 as seen in FIG. 1. Cylinder mount tube 36 is maintained in positionon the cross tube 34 by means of collars 38 and 40 which are positionedat the opposite ends of the cylinder mount tube 36 and which are weldedto the cross tube 34.

Inner cross tube 42 rotatably extends through cross tube 34 and haslocator rings 44 and 46 positioned thereon outwardly of the outer endsof cross tube 34 which are welded to the exterior surface of cross tube42. One end of inner cross tube 42 receives shaft 48 of lower mount 50which is secured to frame member 4. The other end of inner cross tube 42receives shaft 48' of lower mount 50' which is secured to frame member4'. Collars 52 and 52' are mounted on shafts 48 and 48' respectively andare welded thereto at the outer ends thereof. One end of body prop 51 ispivotally mounted on tube 34 outwardly of frame 20 as seen in FIG. 2.Washers 54 and 56 embrace tube 34 on either side of the end of prop 51and are tack welded to tube 34 to maintain body prop 51 in position.

Upper frame assembly 14 includes a pair of longitudinally extending sideframe members 58 and 60 which are in the form of C-shaped channels.Frame member 58 includes a top flange 62, bottom flange 64 and a web 66extending therebetween. Similarly, frame member 60 includes a top flange68, bottom flange 70 and web 72. It can be seen that webs 66 and 72extend inwardly and rearwardly from the forward ends thereof.Additionally, the height of the webs 66 and 72 increases from theforward to rearward ends thereof. Hinge legs 74 and 76 are secured tothe rearward ends of frame members 58 and 60 respectively and have ahinge tube 78 mounted therein which extends between the lower rearwardends thereof which is rotatably mounted on the hinge shaft 28. Torquetube 80 is secured to the inside surfaces of the hinge legs 74 and 76 bywelding and extends therebetween above hinge shaft 28 as seen in FIG. 3.

Cross head shaft 82 is secured to and extends through and between thehinge legs 74 and 76 and has cross head 84 rotatably mounted thereon asseen in FIG. 1. Rod 86 of cylinder 88 is secured to cross head 84 inconventional fashion by a bolt or pin 90. The forward end of cylinder 88is secured to cylinder mount base 92 by bolts 94 and 96 as seen inFIG. 1. Cylinder mount base 92 is welded to cylinder mount tube 36 andhas mounting gussets 98 and 100 at the opposite ends thereof.

As seen in FIG. 1, body prop holddown 102 extends laterally outwardlyfrom frame member 58 and is positioned above the body prop cradle 104which extends laterally from frame member 20 of lower frame assembly 12.Body prop 51 is designed to rest in body prop cradle 104 when not beingused and will be maintained therein when the truck body is in itslowered condition by the body prop holddown 102. The free end of bodyprop 51 is provided with a bracket 105 which is adapted to engage theunderside of upper mount cross tube 108. As seen in the drawings, crosstube 108 is welded to the forward ends of frame members 58 and 60.Locator rings 110 and 112 embrace the ends of inner cross tube 106outwardly of cross tube 108 and are tack welded thereto to rotatablymaintain or locate tube 106 with respect to tube 108.

Upper mounts 114 and 114' are secured to the runsills 8 and 8' of truckbody 6. Mount 114 includes a bracket portion 116 which is secured to runsill 8 and which has shaft 118 extending inwardly therefrom which isrotatably received within the end of tube 106. Similarly, mount 114' issecured to the opposite run sill 8' and has shaft 118' extendinginwardly therefrom which is rotatably received in the other end of thecross tube 106.

Body prop 51 may be selectively maintained in its upright condition bymeans of the prop positioner assembly 120. Assembly 120 includes a pairof spaced-apart upstanding ears or brackets 122 and 124 which are weldedto frame member 20 as seen in FIG. 1. Pin 126 extends between the upperinner ends of ears 122 and 124 and has arm 128 rotatably mountedthereon. Arm 128 has a V-shaped notch 130 formed therein as best seen inFIG. 1. Pin 126 is secured to and extends between ears 122 and 124 tomaintain ar 128 in the horizontal position of FIG. 1. When body prop 51is resting in cradle 104, body prop 51 will be positioned below arm 128.When it is desired to position the body prop 51 in its upright position,after the body 6 has been raised, body prop 51 is simply pivotally movedupwardly until arm 128 has been sufficiently pivoted upwardly to enablearm 128 to then fall downwardly to the horizontal position of FIG. 1.Prop 51 is then pivotally moved downwardly until prop 51 engages notch130 of arm 128 so that prop 51 is maintained in the position of FIG. 4or 5. The body 6 is then lowered until bracket 105 receives the uppermount cross tube 108. Inasmuch as the upper end of prop 51 engages uppermount cross tube 108 and the lower end of prop 51 is in engagement withtube 34, the weight of the body 6 on prop 51 does not put bending forceson the scissor frame. Thus it can be seen that the novel design of thescissor frame lift apparatus of this invention permits the same to beplaced on dump trucks having restricted areas between the frame membersthereof. The narrow scissor hinge, by not being "full width", but havinga width substantially less than the distance between the truck framemembers, permits the apparatus to be mounted on trucks wherein the samewould not normally be possible. The fact that the lift apparatus of thisinvention may be conveniently mounted on modern trucks reduces theamount of time normally required for mounting the body and hoist on sucha truck. The lift apparatus of this invention permits the hoist to bemounted on different sizes and types of equipment. Thus it can be seenthat the invention accomplishes all of its stated objectives.

I claim:
 1. In combination,a truck having a frame including a pair ofhorizontally spaced apart and longitudinally extending frame members, adump body hingedly mounted upon the frame of the truck including a pairof longitudinally extending runsills supporting the understructure ofthe dump body spaced to lie over the frame members of the truck, and ascissor frame lift for raising and lowering said dump body relative tosaid truck frame, said scissor frame lift comprising a lower frameassembly including a horizontally disposed lower mount cross tube meanshaving opposite ends operatively rotatably secured to mounts on theframe members, a pair of lower frame members secured to said lower mountcross tube means, each of said lower frame members including top andbottom flanges having a web extending therebetween, said webs of saidlower frame members extending rearwardly and inwardly from said lowermount cross tube means, said lower frame members being arranged in anon-parallel fashion with respect to each other, a drop hinge legsecured to the rearward end of each of said lower frame members, a hingeshaft secured to and extending between said drop hinge legs; an upperframe assembly including an upper mount cross tube means having oppositeends operatively rotatably secured to mounts on the runsills, a pair ofupper frame members secured to said upper mount cross tube means, eachof said upper frame members including top and bottom flanges having aweb extending therebetween, said webs of said upper frame membersextending rearwardly and inwardly from said upper mount cross tubemeans, said upper frame members being arranged in a non-parallel fashionwith respect to each other, a hinge leg secured to the rearward end ofeach of said upper frame members, said hinge legs being rotatablymounted on said hinge shaft; a cross head shaft secured to and extendingbetween said upper frame members forwardly of said hinge shaft, a crosshead rotatably mounted on said cross head shaft; a hydraulic cylindermeans including a cylinder portion and a rod portion; means connectingsaid rod portion to said cross head; and means operatively rotatablyconnecting said cylinder portion, about a horizontal axis, to said lowerframe members adjacent the forward ends thereof.
 2. The combination ofclaim 1 wherein the horizontal distance between the rearward ends ofsaid webs of said lower frame members is substantially less than thedistance between said truck frame members.
 3. The combination of claim 1wherein said upper mount cross tube means comprises an inner cross tuberotatably positioned within a cross tube, the opposite ends of saidinner cross tube being secured to the mounted on said runsills.
 4. Thecombination of claim 1 wherein the height of the web of said lower framemembers increases from the forward to rearward ends thereof.
 5. Thecombination of claim 1 wherein the width of the bottom flange of each ofsaid upper frame members is less than the width of the top flangethereof to permit the rearward ends of said upper frame members topartially embrace the rearward end of said cylinder.
 6. The combinationof claim 1, wherein said lower mount cross tube means comprises an innercross tube rotatably positioned within a cross tube, the opposite endsof said inner cross tube being secured to the mounts on the framemembers.
 7. In combination,a truck having a frame including a pair ofhorizontally spaced apart and longitudinally extending frame members, adump body hingedly mounted upon the frame of the truck including a pairof longitudinally extending runsills supporting the understructure ofthe dump body spaced to lie over the frame members of the truck, and ascissor frame lift for raising and lowering said dump body relative tosaid truck frame, said scissor frame lift comprising a lower frameassembly including a horizontally disposed lower mount cross tube meanshaving opposite ends operatively rotatably secured to mounts on theframe members, a pair of lower frame members secured to said lower mountcross tube means extending rearwardly and inwardly therefrom, a drophinge leg secured to the rearward end of each of said lower framemembers, a hinge shaft secured to and extending between said drop hingelegs; an upper frame assembly including an upper mount cross tube meanshaving opposite ends operatively rotatably secured to mounts on therunsills, a pair of upper frame members secured to said upper mountcross tube means and extending rearwardly and inwardly therefrom, ahinge leg secured to the rearward end of each of said upper framemembers, said hinge legs being rotatably mounted on said hinge shaft; across head shaft secured to and extending between said upper framemembers forwardly of said hinge shaft, a cross head rotatably mounted onsaid cross head shaft; a hydraulic cylinder means including a cylinderportion and a rod portion; means connecting said rod portion to saidcross head; and means operatively rotatably connecting said cylinderportion, about a horizontal axis, to said lower frame members adjacentthe forward ends thereof; the distance between said hinge legs beingsubstantially less than the distance between the forward ends of saidupper frame members and substantially less than the distance between theforward ends of said lower frame members; each of said lower framemembers being channel-shaped and including a vertically disposed webhaving upper and lower ends, a top flange extending outwardly from theupper end of said web, and a bottom flange extending outwardly from thelower end of said web; each of said upper frame members beingchannel-shaped and having a vertically disposed web with upper and lowerends, a top flange extending inwardly from the upper end of said web,and a bottom flange extending inwardly from the lower end of said web;the width of the top and bottom flanges of said lower frame membersincreasing from the forward to rearward ends thereof.
 8. The combinationof claim 7 wherein the height of the web of said lower frame membersincreases from the forward to rearward ends thereof.
 9. In combination,atruck having a frame including a pair of horizontally spaced apart andlongitudinally extending frame members, a dump body hingedly mountedupon the frame of the truck including a pair of longitudinally extendingrunsills supporting the understructure of the dump body spaced to lieover the frame members of the truck, and a scissor frame lift forraising and lowering said dump body relative to said truck frame, saidscissor frame lift comprising a lower frame assembly including ahorizontally disposed lower mount cross tube means having opposite endsoperatively rotatably secured to mounts on the frame members, a pair oflower frame members secured to said lower mount cross tube means andextending rearwardly and inwardly therefrom, a drop hinge leg secured tothe rearward end of each of said lower frame members, a hinge shaftsecured to and extending between said drop hinge legs; an upper frameassembly including an upper mount cross tube means having opposite endsoperatively rotatably secured to mounts on the runsills, a pair of upperframe members secured to said upper mount cross tube means and extendingrearwardly and inwardly therefrom, a hinge leg secured to the rearwardend of each of said upper frame members, said hinge legs being rotatablymounted on said hinge shaft; a cross head shaft secured to and extendingbetween said upper frame members forwardly of said hinge shaft, a crosshead rotatably mounted on said cross head shaft; a hydraulic cylindermeans including a cylinder portion and a rod portion; means connectingsaid rod portion to said cross head; and means operatively rotatablyconnecting said cylinder portion, about a horizontal axis, to said lowerframe members adjacent the forward ends thereof; one end of an elongatedbody prop being pivotally mounted on one end of said lower mount crosstube of said lower frame assembly, said body prop being selectivelymovable between operative and inoperative positions, said body propbeing substantially horizontally disposed when in its said inoperativeposition, the other end of said body prop adapted to engage and limitthe downward movement of said upper frame assembly when in its saidoperative position.
 10. The combination of claim 9 wherein the other endof said body prop engages the underside of said upper mount cross tubemeans when in its said operative position.
 11. The combination of claim10 wherein means is mounted on said lower frame assembly for properlypositioning said body prop in its said operative position whereby saidbody prop will be in the pivotal path of said upper mount cross tubemeans.
 12. The combination of claim 11 wherein said positioning meansincludes a pivotal arm means which is normally positioned over said bodyprop when said body prop is in its said inoperative position but whichis positioned below said body prop when said body prop is in its saidoperative position.
 13. The combination of claim 9 wherein a holddownmeans is provided for maintaining said body prop in its said inoperativeposition.
 14. In combination,a truck having a frame including a pair ofhorizontally spaced apart and longitudinally extending frame members, adump body hingedly mounted upon the frame of the truck including a pairof longitudinally extending runsills supporting the understructure ofthe dump body spaced to lie over the frame members of the truck, and ascissor frame lift for raising and lowering said dump body relative tosaid truck frame, said scissor frame lift comprising a lower frameassembly including a horizontally disposed lower mount cross tube meanshaving opposite ends operatively rotatably secured to mounts on theframe members, a pair of lower frame members secured to said lower mountcross tube means and extending rearwardly and inwardly therefrom, a drophinge leg secured to the rearward end of each of said lower framemembers, a hinge shaft secured to and extending between said drop hingelegs; an upper frame assembly including an upper mount cross tube meanshaving opposite ends operatively rotatably secured to mounts on therunsills, a pair of upper frame members secured to said upper mountcross tube means and extending rearwardly and inwardly therefrom, ahinge leg secured to the rearward end of each of said upper framemembers, said hinge legs being rotatably mounted on said hinge shaft; across head shaft secured to and extending between said upper framemembers forwardly of said hinge shaft, a cross head rotatably mounted onsaid cross head shaft; a hydraulic cylinder means including a cylinderportion and a rod portion; means connecting said rod portion to saidcross head; and means operatively rotatably connecting said cylinderportion, about a horizontal axis, to said lower frame members adjacentthe forward ends thereof; the distance between said hinge legs beingsubstantially less than the distance between the forward ends of saidupper frame members and substantially less than the distance between theforward ends of said lower frame members.
 15. The combination of a truckhaving a frame including a pair of horizontally spaced apart andlongitudinally extending frame members having a dump body hingedlymounted on the frame of the truck, said dump body including a pair oflongitudinally extending runsills supporting the understructure of thedump body spaced to lie over the frame members of the truck,comprising,a scissor frame lift for raising and lowering said dump bodyrelative to said truck frame, said scissor frame lift comprising a lowerframe assembly including a horizontally disposed lower mount cross tubemeans having opposite ends operatively rotatably secured to mounts onthe frame members, a pair of lower frame members secured to said lowermount cross tube means and extending rearwardly and inwardly therefrom,a drop hinge leg secured to the rearward end of each of said lower framemembers, a hinge shaft secured to and extending between said drop hingelegs; an upper frame assembly including an upper mount cross tube meanshaving opposite ends operatively rotatably secured to mounts on therunsills, a pair of upper frame members secured to said upper mountcross tube means and extending rearwardly and inwardly therefrom, ahinge leg secured to the rearward end of each of said upper framemembers, said hinge legs being rotatably mounted on said hinge shaft; across head shaft secured to and extending between said upper framemembers forwardly of said hinge shaft, a cross head rotatably mounted onsaid cross head shaft; a hydraulic cylinder means including a cylinderportion and a rod portion; means connecting said rod portion to saidcross head; and means operatively rotatably connecting said cylinderportion, about a horizontal axis, to said lower frame members adjacentthe forward ends thereof; the distance between said hinge legs beingless than the distance between the forward ends of said upper framemembers and substantially less than the distance between the forwardends of said lower frame members.
 16. The combination of a truck havinga frame including a pair of horizontally spaced apart and longitudinallyextending frame members having a dump body hingedly mounted on the frameof the truck, said dump body including a pair of longitudinallyextending runsills supporting the understructure of the dump body spacedto lie over the frame members of the truck, comprising,a scissor framelift for raising and lowering said dump body relative to said truckframe, said scissor frame lift comprising a lower frame assemblyincluding a horizontally disposed lower mount cross tube means havingopposite ends operatively rotatably secured to mounts on the framemembers, a pair of lower frame members secured to said lower mount crosstube means, each of said lower frame members including top and bottomflanges having a web extending therebetween, said webs of said lowerframe members extending rearwardly and inwardly from said lower mountcross tube means, said lower frame members being arranged in anon-parallel fashion with respect to each other, a drop hinge legsecured to the rearward end of each of said lower frame members, a hingeshaft secured to and extending between said drop hinge legs; an upperframe assembly including an upper mount cross tube means having oppositeends operatively rotatably secured to mounts on the runsills, a pair ofupper frame members secured to said upper mount cross tube means, eachof said upper frame members including top and bottom flanges having aweb extending therebetween, said webs of said upper frame membersextending rearwardly and inwardly from said upper mount cross tubemeans, said upper frame members being arranged in a non-parallel fashionwith respect to each other, a hinge leg secured to the rearward end ofeach of said upper frame members, said hinge legs being rotatablymounted on said hinge shaft; a cross head shaft secured to and extendingbetween said upper frame members forwardly of said hinge shaft, a crosshead rotatably mounted on said cross head shaft; a hydraulic cylindermeans including a cylinder portion and a rod portion; means connectingsaid rod portion to said cross head; and means operatively rotatablyconnecting said cylinder portion, about a horizontal axis, to said lowerframe members adjacent the forward ends thereof.
 17. In combination,atruck having a frame including a pair of horizontally spaced apart andlongitudinally extending frame members, a dump body hingedly mountedupon the frame of the truck including a pair of longitudinally extendingrunsills supporting the understructure of the dump body spaced to lieover the frame members of the truck, and a scissor frame lift forraising and lowering said dump body relative to said truck frame, saidscissor frame lift comprising a lower frame assembly including ahorizontally disposed lower mount cross tube means having opposite endsoperatively rotatably secured to mounts on the frame members, a pair oflower frame members secured to said lower mount cross tube means, eachof said lower frame members including top and bottom flanges having aweb extending therebetween, said webs of said lower frame membersextending rearwardly and inwardly from said lower mount cross tubemeans, said lower frame members being arranged in a non-parallel fashionwith respect to each other, a drop hinge leg secured to the rearward endof each of said lower frame members, a hinge shaft secured to andextending between said drop hinge legs; an upper frame assemblyincluding an upper mount cross tube means having opposite endsoperatively rotatably secured to mounts on the runsills, a pair of upperframe members secured to said upper mount cross tube, each of said upperframe members including top and bottom flanges having a web extendingtherebetween, said webs of said upper frame members extending rearwardlyand inwardly from said upper mount cross tube, said upper frame membersbeing arranged in a non-parallel fashion with respect to each other, ahinge leg secured to the rearward end of each of said upper framemembers, said hinge legs being rotatably mounted on said hinge shaft; across head shaft secured to and extending between said upper framemembers forwardly of said hinge shaft, a cross head rotatably mounted onsaid cross head shaft; a hydraulic cylinder means including a cylinderportion and a rod portion; means connecting said rod portion to saidcross head; and means operatively rotatably connecting said cylinderportion, about a horizontal axis, to said lower frame members adjacentthe forward ends thereof; said upper mount cross tube means comprisingan inner cross tube rotatably positioned within a cross tube, theopposite ends of said inner cross tube being secured to the mounts onsaid runsills; said lower mount cross tube means comprising an innercross tube rotatably positioned within a cross tube, the opposite endsof said inner cross tube being secured to the mounts on the framemembers. .Iadd.
 18. In combination,a truck having a frame including apair of horizontally spaced apart and longitudinally extending framemembers, each of said frame members having a mount thereon including ahorizontally disposed shaft, a dump body hingedly mounted upon the frameof the truck including a pair of longitudinally extending runsillssupporting the understructure of the dump body spaced to lie over theframe members of the truck, each of said runsills having a mount thereonincluding a horizontally disposed shaft, and a scissor frame lift forraising and lowering said dump body relative to said truck frame, saidscissor frame lift comprising a lower frame assembly and an upper frameassembly, said lower frame assembly including a horizontally disposedlower mount outer cross tube having an inner cross tube mounted therein,the length of said outer cross tube being substantially less than thelength of said inner cross tube, a pair of lower frame members securedto said lower mount outer cross tube; said upper frame assemblyincluding an upper outer cross tube having an inner cross tube mountedtherein, the length of said inner cross tube being substantially greaterthan the length of said outer cross tube, a pair of upper frame memberssecured to said upper outer cross tube; said lower frame members andsaid upper frame members respectively extending rearwardly from saidlower mount and upper outer cross tubes and being operatively pivotallysecured together at their rearward ends, said inner cross tube of saidlower frame assembly being rotatably secured to said shafts of saidmounts on said frame members of said truck, said inner cross tube ofsaid upper frame assembly being rotatably secured to said shafts of saidmounts on said runsills of said dump body, said inner cross tubes havinga substantially greater length than their respective outer cross tubesso that said inner cross tubes may be selectively shortened, withoutshortening said outer cross tubes, as desired to compensate for variouswidths between the frame members of various sizes of trucks. .Iaddend..Iadd.
 19. The combination of claim 18 wherein a positioning means ismounted on each of said inner cross tubes adjacent the opposite ends ofsaid outer cross tubes to maintain said inner cross tubes in positionrelative to said outer cross tubes. .Iaddend.